Case-based reasoning (“CBR”) systems provide diagnostic and analytical assistance in solving problems. CBR systems match the observed characteristics or attribute values of a new problem to those of previously solved cases stored in a database. CBR systems are useful in many fields, from mechanical to medical, in which diagnostic assistance and expertise are helpful in solving problems.
The applicant has obtained U.S. Pat. Nos. 5,822,743 and 6,026,393, which describe improved CBR systems.
CBR systems typically rank potential matching solved cases on the basis of attribute values matching facts known about the problem. For example, an attribute value may be the temperature of a patient or of a component.
Questions are then presented to the user to determine additional attribute values of the new problem, and thereby reduce the number of potential matching solutions. The answers to each question typically require some form of investigation, such as (in a mechanical context) measuring the temperature of a particular component or dissembling a particular component to determine wear patterns. The questions posed are usually ranked by their relevance to the particular problem. Several of the highest ranking questions are presented to the user, who determines which question he or she will investigate and answer next.
The questioning process continues with the answers being used by the CBR system to reduce the number of potential matching cases (and corresponding solutions) until the user is satisfied that the solution to the problem has been located, or is not present in the solved cases database.
While some existing CBR systems, including the applicant's systems described in U.S. Pat. Nos. 5,822,743 and 6026,393, work fairly well, such existing systems do not capture all of the reasoning expertise of experts. Accordingly, the inventor has developed improved CBR systems and methods for ranking potential questions, which more closely emulate the diagnostic analysis conducted by an expert.